1. Field of the Invention
This invention relates to a mold insert for impressing reference indicia into a molded component.
2. Description of the Prior Art
Mold inserts are used in plastic molding processes, as well as other part casting operations, to impress one or more reference indicators into a part. Such indicators as date, time, year, shift, batch number or other indicia are helpful for quality control and other situations that require tracking a manufactured component.
Mold inserts are positioned within a mold such that a portion of the mold insert faces an interior surface of the mold. In this manner, the reference information on the mold insert is directly transferable to the molded component.
One prior art style of mold inserts, such as those commercially available through component distributors, National Tool & Mfg. or D-M-E, for plastic molds, comprises a cylindrical housing having a central insert. An arrow indicator is positioned on a surface of the central insert which is adjustable using a screwdriver. Typically, only one or, at most, two items of information may be indicated on such a mold insert. The relative position of the central insert and the housing is maintained with a threaded central insert in combination with a spring loaded ball bearing.
Boskovic, U.S. Pat. No. 4,384,702, teaches a series of adjacent mold engaging inserts. Each insert is ringed with a separate set of indicia for impressing selected indicia on to the manufactured component. A transverse slot is positioned in a center of each insert. The transverse slot is adjustable with a bladed tool, such as a screwdriver, to direct an indicator toward the proper number within the insert. The indicator maintains its position within the insert with the use of a spring biased retention ring. The Boskovic patent teaches a set of four inserts when four separate series of indicia are required.
Opitz, U.S. Pat. No. 5,620,716, also teaches a spring-tensioned mold insert that maintains position of an arrowhead relative to the time indicia on a circular end face of the mold insert. The Opitz patent only teaches a single ring for a single series of indicia.
Netto, U.S. Pat. No. 4,254,933, teaches a mold insert that permits designation of several series of indicia on an imprinted part. The Netto patent teaches a series of concentric rings rotatable around a reference axis perpendicular to the mold surface. The concentric rings are rotatable in increments, each increment designating a different number or letter from the number or letter in the previous increment. In such manner, the Netto patent teaches a mold insert that maintains and imprints a running count of cycles as successive parts are produced. The rings are incrementally rotated using a system of gears and ratchet teeth.
One common problem with prior art mold inserts are the tendency of the closely toleranced moveable components, such as the indicia rings, to become jammed with the plastic residue or other material used in the molding process. When these moveable components become jammed, any adjustment of the indicia on the mold insert becomes difficult, thus requiring equipment stoppages while the mold insert is removed and cleaned. Often this maintenance is ignored thereby compromising the intended purpose of the insert.